Catoctin Mountain Park provides the landscape where the Mountain Spies story begins. During World War II, the rugged terrain and isolation of the Catoctin Mountains made the area ideal for secret training and experimentation. In 1942, the Office of Strategic Services (OSS), the precursor to the CIA, established a covert paramilitary training site at nearby Camp Greentop known as Camp B-2. Here, small teams trained in sabotage, guerrilla warfare, clandestine communications, and resistance coordination before deploying to occupied Europe. The same protected mountain landscape also hosted the presidential retreat originally called Shangri-La, later renamed Camp David by Dwight D. Eisenhower. The proximity of OSS training, military intelligence activity at Fort Ritchie, and presidential leadership in the Catoctins illustrates how this quiet Appalachian corridor became an important setting for the development of American intelligence and national security during and after World War II.